Fatigue Crack Growth in a Monocrystal and Its Similarity to Short-Crack Propagation in a Polycrystal of Nickel

Autor: Avihai Petel, Ales Jager, Dotan Babai, Juergen Jopp, Arie Bussiba, Mordechai Perl, Roni Z. Shneck
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Metals, Vol 13, Iss 4, p 790 (2023)
Druh dokumentu: article
ISSN: 13040790
2075-4701
DOI: 10.3390/met13040790
Popis: Short fatigue cracks in polycrystalline materials are very important from both practical and basic aspects, yet they are very difficult to observe. Therefore, it is suggested to emulate some properties of short cracks with long fatigue cracks in monocrystals. Indeed, such experiments in pure nickel crystals prove that the three peculiar properties of short fatigue cracks in polycrystalline metals are observed in long cracks in monocrystals, i.e., a lower threshold of the stress intensity factor (ΔKI)th, a higher crack propagation rate at low ΔKI regimes, and the fact that different cracks exhibit different growth behaviors. The fatigue experiments in monocrystals reveal interesting details of the slip activity at the front of fatigue cracks, including a selection rule for the active slip systems above and below the crack, the slip behavior under conditions of steep strain gradients, and the activation of a new slip system.
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